1. Field
The present invention relates to an in-wheel motor vehicle such as, for example, an electric powered car, a fuel cell powered car or any other hybrid car, in which at least two drive wheels of a plurality of drive wheels make use of an in-wheel motor.
2. Description of the Related Art
It has generally been known that in an in-wheel motor vehicle such as, for example, an electric powered car, a fuel cell powered car or a hybrid car in which an in-wheel motor is incorporated in at least two of a plurality of drive wheels, a motor driver of a kind is necessitated, which is comprised of an inverter unit and an inverter control unit in order to control the in-wheel motors. For further discussion, reference will now be made to a related art example shown in FIG. 29. The conventional four wheeled, in-wheel motor vehicle, shown in FIG. 29, makes use of front left and right wheels 32A and 32B and rear left and right wheels 32C and 32D with respective in-wheel motor assemblies 33A to 33D incorporated therein. The in-wheel motor assemblies 33A to 33D are associated with respective motor drivers 34A to 34D that are separately disposed at locations neighboring the corresponding in-wheel motor assemblies 33A to 33D. A direct current electric power is supplied from a vehicle mounted battery 35 to those motor drivers 34A to 34D through a battery control unit 36. A booster circuit may be additionally provided in each of the motor drivers 34A to 34D to increase a power source voltage from the battery 35 for the purpose of increasing the driving efficiency.
As a cooling device for cooling the inverter unit in the motor drive unit of the in-wheel motor vehicle, the use has hitherto been suggested of a cooler capable of absorbing crash energies at the time of the vehicle collision as in Japanese Patent Publication No. H06-303704. According to Japanese Patent Publication No. H06-303704, the motor driver is disposed on one side of the cooler and both of a smoothing capacitor and a DC/DC converter are disposed on the opposite side.
Also, as another related example of the motor driver, a suggestion has been made to use a plurality of control sections, equipped in the motor driver, on both surfaces of a cooler and to use a cooler having a performance lower than the sum of respective calorific values of the control sections as in Japanese Patent Publication No. H07-67213. According to Japanese Patent Publication No. H07-67213, an air conditioner inverter and a DC/DC converter are enumerated as specific examples of the control sections that are disposed on both surfaces of the cooler.
As a further related example, the suggestion has also been made to dispose various inverter, capacitor and a high voltage converter, which are component parts of the motor driver, on an upper surface of a component mount plate and to dispose a control section, a reactor for a high voltage converter, a DC/DC converter and low voltage components, which are associated with the inverter unit, on a lower surface of the component mount plate. In this respect, see Japanese Patent Publication No. 2005-57928.
It has, however, been found that as is the case with the related example shown in and described with reference to FIG. 29, placement of the plurality of the motor drivers 34A to 34D and the boosting circuits requires a substantial space, thus constituting a cause of an increase of the weight and that of the cost. The example disclosed in Japanese Patent Publication No. H06-303704 is applicable to the case in which only one motor driver is used, and Japanese Patent Publication No. H06-303704 does not deal with the use of the plurality of the motor drivers such as in the in-wheel motor vehicle.
In the example disclosed in Japanese Patent Publication No. H07-67213, while the plurality of control sections are disposed on both surfaces of the cooler, only the air conditioner inverter and the DC/DC converter are enumerated as specific examples of the control sections. Although depending on the manner in which the plurality of the control sections are combined, more different effects may be expected, Japanese Patent Publication No. H07-67213 is silent as to the in-wheel motor vehicle having the plurality of the motor drivers and the boosting circuits.
In the example disclosed in Japanese Patent Publication No. 2005-57928, although the total volume of the driving devices may be possibly reduced, an organized large planer space is required in the vehicle and, hence, the space for installation is limited and the degree of freedom of arrangement is also small. Also, since the inverter unit is disposed on the upper surface of the component mount plate and the control sections are disposed on the lower surface thereof, the structure tends to become complicated.
As discussed hereinabove, since in the in-wheel motor vehicle, the plurality of the motor drivers and the boosting circuits are mounted thereon, the space therefore is necessitated and, hence, there is a possibility that the weight and the cost may increase. However, none of Japanese Patent Publication Nos. H06-303704, H07-67213 and 2005-57928 are capable of resolving those problems.